Fire-alarm apparatus.



No. 645,588. I Patented Mar. 20, I900.

A. F. nonnmnse.

FIRE ALARM APPARATUS.

(Application filed 901:. 2B, 1899.)

(No Model.)

UNITED STATES PATENT A OFFICE.

ALBERT F,DODDRIDGE, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO MORTON l\[. CURRY, OF SAME PLACE.

FIRE-ALARM APPARATUS.

$PECIFICATION forming part of Letters Patent No. 645,588, dated March 20, 1900.

I Application filecl October 28, 1899A Serial No. 735,079. (No model.)

To rtlltwhom it may concern:

. Beit known that I, ALBERT F. DODDRIDGE, acitizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Fire-Alarm Apparatus, of which the following is a specification in its best form now known to me, reference being had to the accompanying drawings.

My invention relates to means for automatically sounding an alarm of fire and for simultaneously indicating to the fireman the exact location of the flames.

Many forms of electrical apparatus have heretofore been used whereby the burning of a fusible cut-out or plug near the source of the fire will set off an alarm on the street or in the office and perhaps indicate on an an-' annunciator, if desired,) also continuously rings a bell or other alarm at or near the origin of the fire, or, in other words, near the burned-out plug, whose burning out turned in the alarm, thereby enabling the fireman to locate the exact origin of the fire even though the room may be filled with blinding smoke.

My invention also consists in the method of accomplishing the foregoing results and in the details of construction hereinafter described and claimed.

In the drawings, Figure l is a diagram of my apparatus. Fig.2 is a detailed view of a fusible plug or cut-out used in my apparatus. Fig. 3 is a simplified form of wiring for the relay apparatus.

Throughout the several views similar-letters indicate the same parts.

a represents one of many forms of cut'out her of these plugs are arranged at convenient intervals about a building which is to be pro tected by my apparatus and are connected in series, as shown in Fig. 1. of the drawings I have only-shown three, but any number may be used.- In circuit with these fusible plugs are the batteries and a relay-magnet'l, the wire connecting the batteries-to the magnet being indicated by letter m, and that connecting the magnets to the main wire of the cut-outs by the letter to. It will be seen from an inspection of the drawings that a continuous current flows from the batteries 71? through the wire m, magnet Z, wire n,the cut-outs a, and the wires 6 eback to the batteries. This will hereinafter be referred to as the primary circuit.

Pivoted to the frame of the magnet at 0 and normally held by the current of the pri mary circuit up against 1 he magnet, as shown, is the compound armature having, first, a conducting part 19 adapted when the arma ture falls to the position shown in dotted lines to connect contact-points m and or, through which wires on and n respectively pass, and, second, another conducting part q, (insulated from 19,) adapted when the armature falls to connect contact-points r and s. The contact points 0 and s are connected by the wires r and s to the battery t and the large alarmbell to, so that when the armature falls and q strikes 0" and s a circuit is established through battery 6 and large alarm-bell a, located in the office or on the outside of the For convenience building, whereby the bell is sounded. This minal connected to the wiref of the cut-out and the other terminal to one side of the primary circuit, as shown, so that when the fuse g is burned and the spring I) strikes point d the bell will be thrown into the primary circuit; but as the magnet Z in the primary circuit is of high resistance the bell n will not ring while the magnet remains in circuit, and it is to obviate this difficulty that I insert the contact-points m n in the wires m and 'It, so that when the armature p strikes them the magnet 1 will be shortcircuited and thrown out of the primary circuit substantially simultaneously with the insertion of the bell vinto the circuit, as hereinafter more accurately described.

The operation of my apparatus is as follows: It is installed and normally remains as shown in Fig. 1, with the primary circuit closed through the magnet and the secondary circuit open. It now a fire originates near one of the bells v, the fuse g burns, thereby momentarily breaking the primary circuit, while the spring-switch Z) moves over into contact with (1. During this interval while the current in the primary circuit is broken the armature p (1 falls, cutting magnet Z out of the primary circuit and closing the sec ondary circuit on large bell u. The spring I) has by this time passed into contact with d, and the primary circuit is now reclosed, but the hell i) is substituted for the magnet Z. The two bells it and '2) both continue to ring until the burned-out fuse is replaced or one or both of the circuits are broken by external means. The bell it calls attention to the fact of there being a fire, and the hell 1; indicates its exact location.

The apparatus shown in Fig. 1 represents a single complete unit and may represent'the fuse-plugs on one fioor or one room of a large building. By properly duplicating these units and connecting them to an annunciator in circuit with bell u by any of the common forms of annunciator-wiring the annunciator-bell it may be made to indicate in which unit or section the fire occurs.

The forms and sizes of the cut-outs, the bells, and relays may be varied Within wide limits Without departing from my invention.

Having thus-described myinvention, what I claim as new, and desire to secure by Letters Patent, is

1. In apparatus of the class described, a normally-closed primary circuitconsisting of a fusible plug or cut-out, a relay-magnet adapted, when the circuit is broken, to start an independent alarm mechanism and a source of electrical energy; an alarm-bell adjacent to and so connected with said cut-out that when said fuse is burned out said bell is inserted in said circuit, and means for substantially simultaneously cutting said magnet out of said circuit, substantially as described.

2. In apparatus of the class described, a normally-closed primary circuit consisting of a series of fusible cut-outs or plugs, a relaymagnet, and a source of electrical energy; a normally-open secondary circuit consisting of a source of electrical energy and a large bell or other alarm apparatus; a small bell or other alarm apparatus adjacent to each fusible plug or cut-out, and means whereby when a fusible plug is burned out the secondary circuit is closed on the large bell and the small bell is substituted for the relaymagnet in the primary circuit, substantially as described.

3. In apparatus of the class described, the combination of a normally-closed primary circuit containinga relay-magnet adapted, when the eircuitis momentarily broken, to operate independent alarm mechanism and means whereby when the circuit is sobroken said magnet is short-circuited so as to render it inoperative, substantially as described.

ALBERT F, DODDRIDGE. \Vitnesses:

DWIGHT B. CHEEVER, ROBERT K. S. CATHERWOOD. 

